With regard to the existing touch screens, touch actions are sensed by capacitors, resistors, surface acoustic wave, optical means or the like. Surface acoustic wave touch screen (surface acoustic wave technology) is the only one of existing touch screen technologies in which touch pressure may be sensed. However, the technology, due to shortcomings such as being inapplicable to large-size screens, being too sensitive to surface contaminations, being easy to be disrupted by sound, being difficult to achieve multi-point touch and sense static pressure, or the like, cannot be applied to mainstream devices such as mobile phones, tablet computers or the like. Thus, it is hard to become a mainstream technology. The capacitive touch screen, capable of achieving multi-point touch and having high location sensitivity, is the mainstream touch screen technology at present.
Touch screens, as an important and direct input and output tool for human-machine interaction, are mostly based on two-dimensionality at present. That is, actions of a person who touches the screen in an x-y plane parallel to the screen body may be sensed. As electronic devices are becoming more intelligent and even humanized, more modes are required to be developed for human-machine interaction, for example, a mode in which a machine may be allowed to sense emotion of a person and then make an appropriate response. Applying a touch pressure on an object or on a person is a way for a person to transfer information or emotion, for example, the force applied when playing an instrument, the force applied when painting, explicit expression or implicit expression made in a manner of body touch, or the like. Based on such considerations, a technology in which pressure is regarded as another dimension for human-machine interaction has been researched, where pressure sensing becomes a novel human-machine interaction mode. This technology has broad application prospect.